1. Field of the Invention
The present invention relates to a pick-up for an electrical musical instrument of the stringed type and, more particularly, to a pick-up for an electrical musical instrument of the stringed type having greater versatility with fewer pick-up assemblies than has been achieved heretofore.
2. Description of the Prior Art
The present invention relates broadly to electrical musical instruments of the stringed type. It is particularly applicable to an electrical guitar or similar musical instrument having a plurality of stretched strings extending across a body and a neck, between the head of the instrument and a bridge assembly connected to the body, in which the strings are caused to vibrate by plucking or picking same.
In order to derive an output from such an electrical guitar or other similar electrical musical instrument, the instrument is conventionally provided with an electromagnetic pick-up comprising a number of magnetic elements (pole pieces) having wound therearound a conductive coil. Typically, one such magnetic element is disposed directly beneath each string of the instrument. The strings are constructed of a magnetizable substance, such as steel, and, therefore, become part of the conductive path for the magnetic lines of flux of the pole pieces. Accordingly, when any of the strings are caused to vibrate, this causes a disturbance in the magnetic field of the associated pole piece. This has the effect of generating a voltage in the conductive coil, which voltage may be suitably amplified and transmitted to a loudspeaker system.
With such an electromagnetic pick-up construction, a number of problems exist. Electric guitars and other similar electrical musical instruments are used in areas having strong magnetic fields from lighting fixtures, motors, transformers, and the like, and these magnetic fields are sensed by the pick-up as an extraneous noise source. In the United States, such source typically has a frequency of 60 Hz, the usual power line frequency. These magnetic fields induce voltages in the coil which are also amplified and transmitted to the loudspeaker system, manifesting themselves in an objectionable hum.
In order to overcome this problem, it is known to provide a pick-up for an electrical musical instrument including a pair of identical pick-up assemblies, each having a plurality of magnetic pole pieces and a coil, the pick-up assemblies being positionable in parallel, spaced, closely adjacent relationship. All of the pole pieces of one of the pick-up assemblies have their north poles adjacent to the strings and their south poles relatively remote from the strings whereas all of the pole pieces of the other pick-up assembly have their south poles adjacent to the strings and their north poles relatively remote from the strings. The coils of the two pick-up assemblies are wound in opposite directions and the two coils are connected either in series or in parallel. Because the direction of current flow in each coil is governed by the magnetic polarity, the direction of current flow in one coil is opposite to that of the other coil for each string. However, since the directions of the windings of the two coils are opposite, the signal induced in each coil as a result of string vibrations is additive and the output signal is the sum of the signals induced in each coil.
On the other hand, signals picked up by the coils from power line sources produce currents in the coils which are independent of the magnetic polarity and, accordingly, such power line sources produce voltages that are in phase. However, since the coils are wound in opposite directions, these in phase signals cancel and the output signal is the difference between the power line signals induced in each coil. This means that any noise from power line sources, which is otherwise manifested as an objectionable hum, is effectively reduced or cancelled. It is for this reason that such an arrangement is typically characterized as a humbucking arrangement.
From the above it can be seen that whenever it is desired to have a humbucking arrangement, it is necessary to have pairs of pick-up assemblies. Thus, it is common for electrical musical instruments to have two, four or six pick-ups. It would be desirable to be able to minimize the number of pairs of pick-up assemblies while still having a humbucking arrangement.
It is also common to sum the inputs from the different pairs of pick-up assemblies into a preamplifier before conducting the signal from the pick-up assemblies to the amplification system. Occasionally, the preamplifier becomes inoperative either because of problems associated therewith or because the batteries which run same within the instrument go dead. In such case, only the main coils are conducted to the amplification system and the humbucking pairs are not used. In such case, it would be desirable to maximize the signal and to still, if possible, have a humbucking arrangement. Other problems are further addressed herein.